Microwave Food Container

ABSTRACT

A microwave food container which includes one or more oil-resistant areas including an oil-resistant substance for preventing penetration of the microwave food container by liquids such as oils or grease. The microwave food container generally includes a top portion, bottom portion, and pair of side portions. A food item and optional oil-producing substance may be positioned on a microwave susceptor film including a microwave interactive material for applying heat from a microwave oven to cook the food item. One or more areas of the interior of the microwave food container will generally include oil-resistant areas treated with an oil-resistant substance not including fluorocarbons or PFA&#39;s to prevent penetration or bleed-through of various liquids during the cooking process.

CROSS REFERENCE TO RELATED APPLICATIONS

Not applicable to this application.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable to this application.

BACKGROUND

The described example embodiments in general relate to a microwave food container for heating a food item in a microwave oven which includes a microwave susceptor film and/or oil-resistant areas including an oil-resistant substance to prevent penetration of the microwave food container by liquids such as oil, grease, fat, and the like caused by the heating of food items stored within the microwave food container. More particularly, example embodiments relate to a microwave popcorn bag for popping popcorn in a microwave oven.

A microwave food container for heating a food item in a microwave oven, such as a microwave popcorn bag, can be constructed of a fibrous material such as a paper product. The microwave food container generally includes a microwave susceptor film for converting microwave energy generated by a microwave source, e.g., the microwave oven, to thermal energy. The thermal energy in turn heats a food item contained in the container, such as kernels of popcorn in a bag, in order to cook the food item or, in the case of popcorn kernels, to cause them to pop. The microwave food container may also contain a flavored or non-flavored cooking oil-producing substance which liquefies as it is heated with the food item. In the case of popcorn kernels, the heated liquefied cooking oil helps cause the kernels to pop and helps the popped corn stay moist and resist burning. Other food items also may produce oil-containing and/or other juices as it cooks.

After manufacture, a microwave popcorn bag or other microwave food container can spend a considerable amount of time in transit and/or in storage prior to being used. As a result, oil and/or grease from the popcorn or other food item, and/or from an oil-producing substance, in the bag or other container can spend a considerable amount of time in contact with the fibrous material of the bag or other container. With such extended contact, there is a substantial risk of the oil and/or grease penetrating into and even through the fibrous material. In addition, while the bag or other container is in use and as the popcorn or other food item in the bag or other construct is heated, liquefied cooking oil and/or oil-containing juices can penetrate into and through the fibrous material. Penetration of oil, grease, and/or other juices into the fibrous material can stain the bag or other construct, which is unattractive to consumers. In addition, leakage through the fibrous material can result in a mess inside and outside of the bag or other construct, including inside a microwave.

To prevent penetration and leakage, the fibrous material may be sprayed or otherwise treated with certain chemical substances that resist penetration of the oil and/or other juices into and through the fibrous material. For example, the fibrous material can be treated with certain fluorocarbon (FC)-containing substances which penetrate and permeate the fibrous material. When applied to fibrous materials, such FC-containing substances are generally effective at repelling oil and oil-containing liquids. However, some FC-containing substances may include PFAS (per- and polyfluoroalkyl substances) and for various reasons some retail and wholesale customers desire not to use fibrous packaging containing PFAS. In addition, some manufacturers of some of the FC-containing substances are discontinuing the use of FC-based grease proof coatings and chemistries.

Accordingly, there is a need to address the problem of oil, grease, and/or other oil-containing juices penetrating into and through microwave food containers in general, and more specifically microwave popcorn bags, that are made of fibrous materials such as paper products, but without using FC-containing chemical substances. As described and claimed below, the systems and methods described herein provide a unique microwave food container including a microwave susceptor film and/or oil-resistant areas to protect against penetration of the fibrous material forming the microwave food container by various liquids. More specifically, the systems and methods described herein relate to a microwave popcorn bag including microwave susceptor film and/or one or more oil-resistant areas that address this need as well as others.

SUMMARY

Some of the various embodiments of the present disclosure relate to a microwave food container, such as a microwave popcorn bag, that incorporates one or more oil-resistant areas to protect the microwave food container from penetration by various liquids such as oils, grease, and the like. The microwave food container may comprise a rigid, semi-rigid, or flexible material such as a fibrous material. The microwave food container will generally include a bottom portion, a top portion, and a pair of side portions. The microwave food container may include a microwave susceptor film applied to one or more areas of its interior surface, such as but not limited to the bottom portion. The microwave susceptor film may include a microwave interactive material for applying heat from a microwave oven to food items stored within the microwave food container. The microwave food container may include one or more oil-resistant areas, each including an oil-resistant substance. The oil-resistant substance will generally not include any fluorocarbons or PFA's. The positioning, location, and orientation of the oil-resistant areas may vary in different embodiments.

There has thus been outlined, rather broadly, some of the embodiments of the present disclosure in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional embodiments of that will be described hereinafter and that will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment in detail, it is to be understood that the various embodiments are not limited in its application to the details of construction or to the arrangements of the components set forth in the following description or illustrated in the drawings. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.

To better understand the nature and advantages of the present disclosure, reference should be made to the following description and the accompanying figures. It is to be understood, however, that each of the figures is provided for the purpose of illustration only and is not intended as a definition of the limits of the scope of the present disclosure. Also, as a general rule, and unless it is evidence to the contrary from the description, where elements in different figures use identical reference numbers, the elements are generally either identical or at least similar in function or purpose.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a microwave food container in accordance with an example embodiment.

FIG. 2A is a sectional view of a microwave food container including a pair of oil-resistant areas in accordance with an example embodiment.

FIG. 2B is a sectional view of a microwave food container including a pair of oil-resistant areas in accordance with an example embodiment.

FIG. 2C is a sectional view of a microwave food container including a pair of oil-resistant areas in accordance with an example embodiment.

FIG. 3 is a perspective view of a microwave food container in an expanded state in accordance with an example embodiment.

FIG. 4A is a sectional view of a microwave food container in an expanded state including a pair of oil-resistant areas in accordance with an example embodiment.

FIG. 4B is a sectional view of a microwave food container in an expanded state including a pair of oil-resistant areas in accordance with an example embodiment.

FIG. 4C is a sectional view of a microwave food container in an expanded state including a pair of oil-resistant areas in accordance with an example embodiment.

FIG. 5A is a top view of a blank for a microwave food container including a pair of oil-resistant areas adjacent to a microwave susceptor film in accordance with an example embodiment.

FIG. 5B is a top view of a blank for a microwave food container including a pair of oil-resistant areas adjacent to a microwave susceptor film in accordance with an example embodiment.

FIG. 5C is a top view of a blank for a microwave food container including a pair of oil-resistant areas distally spaced with respect to a microwave susceptor film in accordance with an example embodiment.

FIG. 6A is a sectional end view of a microwave food container including a pair of oil-resistant areas adjacent to a microwave susceptor film in accordance with an example embodiment.

FIG. 6B is a sectional end view of a microwave food container including a pair of oil-resistant areas adjacent to a microwave susceptor film in accordance with an example embodiment.

FIG. 6C is a sectional end view of a microwave food container including a pair of oil-resistant areas distally spaced with respect to a microwave susceptor film in accordance with an example embodiment.

FIG. 7A is a top view of a blank for a microwave food container including a pair of oil-resistant areas adjacent to a microwave susceptor film in accordance with an example embodiment.

FIG. 7B is a top view of a continuous roll stock including multiple blanks for a microwave food container including a pair of oil-resistant areas adjacent to a microwave susceptor film in accordance with an example embodiment.

FIG. 7C is a top view of a continuous roll stock including multiple blanks for a microwave food container including a pair of oil-resistant areas adjacent to a microwave susceptor film in accordance with an example embodiment.

FIG. 8A is a top view of a blank for a microwave food container including greater than two oil-resistant areas adjacent to a microwave susceptor film in accordance with an example embodiment.

FIG. 8B is a top view of a continuous roll stock including multiple blanks for a microwave food container including greater than two oil-resistant areas adjacent to a microwave susceptor film in accordance with an example embodiment.

FIG. 8C is a top view of a continuous roll stock including multiple blanks for a microwave food container including greater than two oil-resistant areas adjacent to a microwave susceptor film in accordance with an example embodiment.

DETAILED DESCRIPTION A. Overview

As shown throughout the figures, an exemplary microwave food container 10 may comprise a bottom portion 34 including an interior surface 40 adapted to support a food item 44 such as a plurality of popcorn kernels. A top portion 28 may be interconnected with the bottom portion 34 for enclosing an interior space 38 of the microwave food container 10. A first side portion 22 a and a second side portion 22 b may be connected between the top and bottom portions 28, 34 of the microwave food container 10 so as to define the interior space 38 in which the food items 44 are stored and cooked.

A microwave susceptor film 50 may be positioned on the interior surface 40 of the microwave food container 10, such as on the interior surface 40 of the bottom portion 34, with the microwave susceptor film 50 being adapted to receive microwaves and apply heat to the food items 44 such as plurality of popcorn kernels. A first oil-resistant area 33 a may be positioned on a first side 54 of the microwave susceptor film 50 and a second oil-resistant area 33 b may be positioned on a second side 55 of the microwave susceptor film 50, with each of the first and second oil-resistant areas 33 a, 33 b comprising an oil-resistant substance 32.

The first and second oil-resistant areas 33 a, 33 b may each be on the bottom portion 34 of the microwave food container 10. The first oil-resistant area 33 a may be adjacent to the first side 54 of the microwave susceptor film 50 and the second oil-resistant area 33 b may be adjacent to the second side 55 of the microwave susceptor film 50. The first oil-resistant area 33 a may be distally spaced with respect to the first side 54 of the microwave susceptor film 50 and the second oil-resistant area 33 b may be distally spaced with respect to the second side 55 of the microwave susceptor film 50. The first oil-resistant area 33 a may extend from the bottom portion 34 to the first side portion 22 a and the second oil-resistant area 33 b may extend from the bottom portion 34 to the second side portion 22 b.

In some embodiments, the first side portion 22 a may comprise a first gusset 23 a with a first fold line 26, with the first oil-resistant area 33 a extending across the first fold line 26. The second side portion 22 b may comprise a second gusset 23 b with a second fold line 26, with the second oil-resistant area 33 b extending across the second fold line 26. The oil-resistant substance 32 in some embodiments does not include perfluoroalkyl or polyfluoroalkyl substances.

The first oil-resistant area 33 a may extend into the first side portion 22 a the entire distance between the bottom portion 34 and the top portion 28. The second oil-resistant area 33 b may extend into the second side portion 22 b the entire distance between the bottom portion 34 and the top portion 28. The first oil-resistant area 33 a, the second oil-resistant area 33 b, and the microwave susceptor film 50 may each comprise the same size. The microwave susceptor film 50 may include a microwave interactive material 52. The bottom portion 34, top portion 28, and side portions 22 a, 22 b may each be comprised of a fibrous material.

In some embodiments, the microwave food container 10 may comprise a third oil-resistant area 33 c near a top 56 of the microwave susceptor film 50 and/or a fourth oil-resistant area 33 d near a bottom 57 of the microwave susceptor film 50 with each of the third and fourth oil-resistant areas 33 c, 33 d comprising an oil resistant substance 32.

B. Microwave Food Container

As best shown in FIGS. 1-4C, a microwave food container 10 such as a microwave popcorn bag may be utilized for storing and heating microwave popcorn or another microwave food item such as but not limited to pork rinds, puff pellets, and the like. In some embodiments, different types of microwave food containers 10 may be utilized for the same or a different type of microwave food item. By way of example and without limitation, such constructs (other than a microwave popcorn bag) may comprise a carton, box, or various other types of microwavable containers known in the art for heating various types of microwavable food items.

The microwave food container 10 may be comprised of various types of materials, such as a fibrous material (e.g., a paper-based material such as cardboard or the like). The microwave food container 10 may be comprised of a single or multiple layers of a fibrous material such as a paper-based material. As a non-limiting example, the microwave food container 10 may comprise a single thin layer of a paper-based material, or may be comprised of a laminate of multiple layers of one or more paper-based materials. In the embodiment shown in FIGS. 2A-2C and 4A-4C, it can be seen that the microwave food container 10 may comprise an outer layer 62 and an inner layer 64, each comprised of a fibrous material such as a paper-based material.

The fibrous material may be relatively thin and flexible to allow the microwave food container 10 to be expandable as described herein. However, in some embodiments, the fibrous material may be thick or stiff. By way of a non-limiting example, the fibrous material may comprise paperboard or cardboard. Such alternate materials may be sued with various microwaveable food items and are thus intended to be encompassed within the scope of the disclosure herein. In this regard, the type of material used for the microwave food container 10 should not be construed as limited to any particular type of fibrous material (e.g., thin or thick, flexible or rigid, etc.).

While the figures show a microwave food container 10 comprised of a microwave popcorn bag, it should be appreciated that the microwave food container 10 may be adapted to store or contain various microwave food items 44, such as but not limited to popcorn kernels, sandwiches, pork rinds, puff pellets, burritos, pastas such as macaroni and cheese, tacos, quesadillas, rice products such as fried rice, and various other foods that may be heated in a microwave. In the embodiment shown in the figures, the microwave food container 10 is illustrated as comprising an expandable microwave popcorn bag comprised of a fibrous material.

In some embodiments such as shown in FIGS. 2A-2C, the microwave food container 10 may be adapted to contain an oil-producing substance 46 which aids in heating the food items 44 contained within it, such as popcorn kernels. The oil-producing substance 46 may be included so as to, for example, apply heat and moisture to a food item lacking the requisite moisture to properly heat up without it. Additionally, the oil-producing substance 46 may also prevent the food item 44 from becoming burned as is the case with popcorn kernels.

It should be appreciated that the oil-producing substance 46 may in some embodiments be omitted, such as when the food item 44 being stored in the microwave food container 10 and heated in the microwave would not need any oil for efficient and proper heating. In embodiments where it is used, the oil-producing substance 46 may, for example, comprise a semi-solid cooking grease or fat capable of being melted or liquefied upon application of heat (e.g., through microwave radiation) so as to produce a liquid cooking oil substance. The oil-producing substance 46 may also include various other flavoring components such as butter, salt, seasoning, or the like.

In the embodiment shown in FIGS. 1-4C, the microwave food container 10 is illustrated as comprising a microwave popcorn bag which is constructed of a single, continuous piece of fibrous material. In some embodiments such as shown in FIGS. 1-4C, the microwave popcorn bag may comprise a single piece of a multi-layered laminate of fibrous material. The microwave popcorn bag may initially be substantially flat upon manufacture, and be adapted to inflate with air (e.g., from expanding popcorn kernels) when heated.

As shown in FIGS. 1 and 3 , the microwave food container 10 may include a first end portion 12, a second end portion 18, a top portion 28, a bottom portion 34, and first and second side portions 22 a, 22 b which together define an interior space 38. The first and second end portions 12, 18 are arranged to be substantially opposed to each other. Similarly, the top portion 28 and the bottom portion 34 are also arranged substantially opposed to each other.

As shown in FIGS. 1-4C, a first side portion 22 a is connected between a first side of the top portion 28 and a first side of the bottom portion 34, and a second side portion 22 b is connected between a second side of the top portion 28 and a second side of the bottom portion 34 substantially opposite of the first side portion 22 a. The top and bottom portions 28, 34 may be adhered together at the first end portion 12 so as to form a first end portion seal 14. Similarly, the top and bottom portions 28, 34 may be adhered together at the second end portion 18 so as to form a second end portion seal 20.

The first and second side portions 22 a, 22 b are generally arranged to be substantially opposed to each other. Each of the first and second side portions 22 a, 22 b may extend substantially completely between and join together the top and bottom portions 28, 34, preferably at or near opposite outer edges of the top portion 28 and the bottom portion 34 respectively. Each of the first and second side portions 22 a, 22 b also may also extend substantially completely along the opposite outer edges of the top and bottom portions 28, 34 between the first end portion 12 and the second end portion 18 including the first end portion seal 14 and the second end portion seal 20.

As best shown in FIGS. 2A-2C and 4A-4C, an interior space 38 have an interior volume is defined between the top portion 28, first and second side portions 22 a, 22 b, bottom portion 34, and end portion seals 14, 20. The microwave food container 10 also includes an interior surface 40 facing towards the interior space 38, and an exterior surface 42 facing away from the interior space 38 opposite to the interior surface 40. The interior space 38 is adapted to store or contain the food item 44 such as popcorn kernels. The interior space 38 may also be adapted to store or contain an optional oil-producing substance 46 and/or other items (e.g., flavorings, seasoning, oils, juices, fats, and the like).

The interior space 38 may have a first size prior to being heated, such as at any time between manufacture and being heated (e.g., when the microwave food container 10 is being stored or transported). The interior space 38 may expand into a second size greater than the first size, such as with air or other gasses, upon the food item 44 being heated.

In the exemplary embodiment shown in FIGS. 2A-2C and 4A-4C, the interior surface 40 of the microwave food container 10 may be comprised of an interior surface of a laminated fibrous material. The interior surface 40 may be exposed to or come in contact with the food item 44, any optional oil-producing substances 46, and various other oils, greases, juices, liquids, fats, seasonings, and the like in various locations during transit, storage, and use. The interior surface 40 of the bottom portion 34 and side portions 22 a, 22 b is particularly likely to come into contact with various items or substances, such as the foregoing. The interior surface 40 of the top portion 28 may also be exposed if the microwave food container 10 is stored or transported upside-down. These areas are thus particularly at-risk for penetration by oil or various other liquids which may bleed into and through the laminated fibrous material from which some embodiments of the microwave food container 10 may be constructed.

As shown in FIGS. 1-4C, the exterior surface 42 of the microwave food container 10 will generally be comprised of the exterior surface of the outer layer 62 of the microwave food container 10. The exterior surface 42 will generally be exposed to the environment external to the microwave food container 10 and preferably will not be directly exposed or contacted by the food item 44 or various other items or substances stored within the interior space 38 (e.g., oil-producing substances 46, oils, liquids, juices, and the like).

The exterior surface 42 is readily visible to users, and thus indicia may be provided on the exterior surface 42 for various functions, such as displaying trademarks, providing nutritional information, instructions, labeling, identification, and the like relating to the food items 44 stored within the interior space 38 of microwave food container 10. Such indicia may be placed on any of the various portions 22 a, 22 b, 28, 34 of the microwave food container 10.

FIGS. 1-2C illustrate the microwave food container 10 following manufacture and prior to use, with the microwave food container 10 being relatively compact and having a relatively flat, unexpanded profile. The food items 44 stored therein, such as popcorn kernels, are generally introduced within the interior space 38 during the manufacturing process. However, in some embodiments, the microwave food container 10 may be sold separately to the consumer, with the consumer herself placing the food items 44 within the microwave food container 10 prior to heating in a microwave oven.

FIGS. 2A-2C illustrate food items 44 comprised of popcorn kernels and an oil-producing substance 46 positioned within the interior space 38 of the microwave food container 10. As shown, the food items 44 and oil-producing substance 46 may be supported on and in contact with various areas on the interior surface 40 of the microwave food container 10.

As an example, the food items 44 and oil-producing substance 46 may contact the bottom portion 34 of the microwave food container 10. As a further example, the food items 44 and oil-producing substance 46 may come in contact with the interior surface 40 of the first and second side portions 22 a, 22 b, particularly areas that are adjacent to or near the bottom portion 34. As shown in FIGS. 2A-2C, the food item 44 and oil-producing substance 46 may be contact with the interior surface 40 of the inner layer 64 of fibrous material for long lengths of time between manufacture and heating (e.g., during transit to a store shelf, during display on the store shelf, and within a purchaser's home prior to heating). When a purchaser desires to consume the food item 44 within the microwave food container 10, the microwave food container 10 is generally positioned within a microwave oven, preferably oriented with the bottom portion 34 and microwave susceptor film 50 being supported on the platform of the microwave oven. The food item 44 and oil-producing substance 46 are positioned on the microwave susceptor film 50, which is adapted to receive microwave energy from the microwave oven and apply heat to the food item 44 and oil-producing substance 46 in the microwave food container 10.

In the exemplary embodiment in which the food item 44 is comprised of popcorn kernels, the popcorn kernels are heated and pop, generating gasses in the interior space 38 of the microwave food container 10. The popped kernels also increase in volume and begin to fill the interior space 38 such as shown in FIGS. 3-4C.

Accordingly, as shown in FIGS. 1-4C, the microwave food container 10, including the interior space 38, is generally made expandable to accommodate the expansion of the gases and the volume of the popped kernels. However, it will be appreciated that food items 44 different than popcorn may not require the microwave food container 10 to be expandable or may require a lesser or greater degree of expandability. Accordingly microwave food containers 10 exhibiting no or varying degrees of expansion are contemplated and are intended to be within the scope of the present disclosure.

The manner by which the microwave food container 10 is made expandable may vary in different embodiments. In the exemplary embodiment shown in the figures, it can be seen that the microwave food container 10 includes a first side portion 22 a including a first gusset 23 a and a second side portion 22 b including a second gusset 23 b. As shown in FIGS. 4A-4C, each gusset 23 a, 23 b may include at least a first fold area 24 adjacent to the top portion 28 and a second fold area 24 adjacent to the bottom portion 34. Each of the fold areas 24 are shown as extending substantially the entire distance between the first and second end portions 12, 18 of the microwave food container 10.

Each of the gussets 23 a, 23 b may include three substantially parallel fold lines 26 located between the top portion 28 and the bottom portion 34 of the microwave food container 10 and extending substantially the entire distance between the first and second end portions 12, 18 of the microwave food container 10. The first fold line 26 adjacent to the top portion 28 may join the top portion 28 to the side portion 22 a, 22 b. The second fold line 26 adjacent to the bottom portion 34 may join the bottom portion 34 to the same respective side portion 22 a, 22 b. The third fold line 26 may be located between the first and second fold lines 26 and between adjacent fold areas 24 so as to join the adjacent fold areas 24 together.

As shown in FIGS. 1-2C, prior to being heated (e.g., by a microwave oven), the microwave food container 10 may have a relatively flat and compact profile with the fold areas 24 of the gussets 23 a, 23 b in each of the first and second side portions 22 a, 22 b being substantially folded in on each other along the fold lines 26. The top and bottom portions 28, 34 are relatively closely spaced, and the interior space 38 of microwave food container 10 has a relatively small interior volume which is sufficient to contain the unheated popcorn kernels or other food item 44 and the optional oil-producing substance 46 in contact with and supported on the bottom portion 34 and the microwave susceptor film 50. The unheated popcorn kernels and the optional oil-producing substance 46 may also be in contact with at least portions of one or both of the gussets 23 a, 23 b in the first and second side portions 22 a, 22 b, e.g., the fold areas 24 and fold lines 26 that are located near or adjacent to the bottom portion 34.

As the popcorn kernels or other food item 44 and the optional oil-producing substance 46 are heated in a microwave oven, the kernels pop, gases are generated, and the popped kernels begin to expand and fill the interior space 38 of the microwave food container 10. As shown in FIGS. 3-4C, the resulting pressure pushes outward from the interior space 38 of the microwave food container 10 against the interior surface 40 and causes the fold areas 24 of the gussets 23 a, 23 b in each of the first and second side portions 22 a, 22 b to unfold from each other along the respective fold lines 26 and the side portions 22 a, 22 b. This also causes the side portions 22 a, 22 b, the top portion 28, and the bottom portion 34 to move outwardly away from each other and the volume of the interior space 38 to expand until the microwave food container 10 is substantially completely expanded as shown in FIGS. 3-4C.

It will be appreciated that while one example of suitable gussets 23 a, 23 b are shown and described, smaller or larger gussets 23 a, 23 b comprising fewer or more fold areas 24 and fold lines 26 may be used depending on the degree to which it is desired for the microwave food container 10 to be expandable (e.g., to accommodate different volumes or types of food items 44). Further, the gussets 23 a, 23 b may occupy a greater or smaller portion of the first and second side portions 22 a, 22 b. Still further, the gussets 23 a, 23 b may be included in both the first and second side portions 22 a, 22 b or only in one of the side portions 22 a, 22 b. All such variations are contemplated and are thus intended to be included within the scope of the present disclosure.

It also will be appreciated that during the heating process, at least a portion of the popcorn kernels or other food item 44, the oil-producing substance 46 if present, and/or other oils, oil-containing liquids, and/or juices resulting from heating the food item 44 are likely to remain or come in contact with various areas of the interior surface 40 of the microwave food container 10, such as but not limited to the bottom portion 34, the side portions 22 a, 22 b, and/or, in some embodiments, the top portion 28.

Generally speaking, the bottom portion 34 and the gussets 23 a, 23 b of the side portions 22 a, 22 b that are adjacent to the bottom portion 34, including one or more fold areas 24 and/or fold lines 26, are at an increased risk of being penetrated by oils, juices, fats, liquids, or the like during heating, which may cause leakage. To protect against such occurrences, the microwave food container 10 may include oil-resistant areas 33 a, 33 b which have been treated with an oil-resistant substance 32 as discussed herein. The microwave susceptor film 50 itself may also provide protection against such penetration. Generally, a combination of the microwave susceptor film 50 and one or more oil-resistant areas 33 a, 33 b will reduce or eliminate the risk of penetration into and through the fibrous material of the microwave food container 10 by oils, liquids, juices, and the like in these locations.

As best shown in FIG. 1 , prior to the microwave food container 10 being heated, the first end portion 12 and second end portion 18 are substantially closed by the respective first and second end portion seals 14, 20. This substantially seals the interior space 38 of the microwave food container 10 from the external environment so as to prevent contamination of any food items 44 prior to heating. FIG. 3 illustrates a microwave food container 10 in the form of a microwave popcorn bag for heating food items 44 comprised of popcorn kernels, with the first end portion seal 14 having or producing during the heating process a first end portion opening 16 which allows gasses generated in the interior space 38 during heating to be vented and to escape into the external environment. When the heating process is completed, the first end portion opening 16 may be expanded (e.g., by pulling it open) to allow the purchaser to easily access the heated food item 44 within the interior space 38 of the microwave food container 10.

Accordingly, during the manufacturing process of microwave food container 10, the first end portion seal 14 initially may be adhered together continuously or discontinuously across all or a portion of the distance it extends between the first and second side portions 22 a, 22 b with an appropriate non-toxic food grade sealant. In at least one portion of the first end portion seal 14, the sealant may be thinner or otherwise less adherent so that as the popcorn kernels pop and the microwave popcorn bag expands, the forces acting to pull the first end portion seal open will overcome the sealing force of the temporary sealant and produce or expand the first end opening 16 in the first end portion seal 14 to allow the gasses to escape. The sealing force provided by the temporary sealant to the remainder of the first end portion seal 14 is preferably weak enough so that when the heating process is completed, a purchaser may easily expand the first end opening 16 and open the first end portion seal 14 to gain access to the contents of the microwave food container 10.

In contrast to the first end portion seal 14, the second end portion seal 20 may be permanently sealed with a suitable non-toxic food grade sealant. It will be appreciated however that instead of or in addition to the first end portion seal 14 being provided with a first end portion opening 16 for venting gases and accessing the contents of the microwave food container 10, the second end portion seal 20 may be provided with an opening in the same manner and for the same uses. Any such variations are contemplated and are considered to be within the scope of the disclosure herein.

It will be appreciated that while the example embodiment of the microwave food container 10 illustrated in the figures has a generally box-like configuration with four substantially rectangular panels or portions 22 a, 22 b, 28, 34, other configurations are also possible and will benefit from the features disclosed herein. For example, an alternative configuration could have a substantially circular or otherwise rounded bottom portion 34 with a single continuous side portion 22 a that extends substantially around the periphery of the bottom portion 34. The side portion 22 a could be non-expandable, expandable with a plurality of defined fold areas 24, or even expandable without defined fold areas 24. This and other alternative configurations that are consistent with and can employ one or more of the various features described herein are contemplated and considered to be within the scope of the disclosure.

C. Microwave Susceptor Film

As shown in FIGS. 5A-8C, the microwave food container 10 may include a microwave susceptor film 50. FIGS. 2A-2C, 4A-4C, and 6A-6C illustrate a microwave susceptor film 50 that is laminated between the outer and inner layers 62, 64 of fibrous material from which the microwave food container 10 is made. It should be appreciated, however, that in some embodiments the microwave susceptor film 50 may be applied instead to the interior surface 40 of the microwave food container 10, such as to the outer layer 62.

The location of the microwave susceptor film 50 may vary for different microwave food containers 10 and different food items 44. In the exemplary embodiment shown in the figures, the microwave susceptor film 50 is illustrated as being located in the bottom portion 34. In some embodiments, the microwave susceptor film 50 may extend into at least portions of the side portions 22 a, 22 b that are adjacent to the bottom portion 34 of the microwave food container 10. The microwave susceptor film 50, the inner layer 64, and the outer layer 62 of the fibrous material can be adhered together and laminated using a non-toxic food grade adhesive that has suitable adherence and thermal properties for use in the microwave food heating applications contemplated herein.

The figures illustrate usage of a single, rectangular or square-shaped microwave susceptor film 50 on the interior surface 40 of the microwave food container 10. It should be appreciated that the shape, positioning, location, orientation, size, and thickness of the microwave susceptor film 50 may vary in different embodiments to suit different microwave food containers 10 and/or food items 44. By way of non-limiting example, there could be multiple, discrete microwave susceptor films 50 at different positions within the microwave food container 10 such as, e.g., one or more microwave susceptor films 50 on the bottom portion 34, one or more microwave susceptor films 50 on one or both of the side portions 22 a, 22 b, and/or one or more microwave susceptor films 50 on the top portion 28. Such a configuration could allow the microwave susceptor film 50 to completely or substantially surround various food items 44.

The microwave susceptor film 50 may comprise various materials known to safely heat in response to application of microwave energy from a microwave oven, such as but not limited to a film of non-toxic food grade material that is resistant to penetration by oil, grease, and other oil-containing juices and liquids. In addition, the microwave susceptor film 50 may comprise an environmentally friendly, biodegradable cellulosic material, such as cellophane film. Other film materials may also be suitable, including but not limited to thermoplastic polymers such as polyethylene terephthalate (also known as PET or polyester), various other polyesters, and the like.

The microwave susceptor film 50 generally includes a first surface and a second surface that is arranged opposite to the first surface. A microwave interactive material 52 may be present on one of the first and second surfaces. When the microwave susceptor film 50 is laminated with the fibrous material, the microwave interactive material 52 may be adjacent to and in contact with the inner layer 64 of the fibrous material. As described further herein, the microwave interactive material 52 will generally occupy only a portion of one of the first and second surfaces and not the entire area of the surface.

The microwave interactive material 52 may comprise a coating of aluminum or another suitable metal, metal alloy, or other material. As a non-limiting example, the microwave interactive material 52 may comprise certain ceramic or other materials that are capable of converting microwave energy to thermal energy. In the case of a metal or metal alloy material, such as aluminum, the microwave interactive material 52 can be applied directly to a surface of the microwave susceptor film 50 by spray coating, vacuum deposition, direct printing, or any other suitable process. Such processes may also include de-metallization processes. It is contemplated that such processes may be useful in certain embodiments and therefore both direct application processes and de-metallization processes are intended to be encompassed within the scope of the present disclosure.

Similarly, in the present example embodiment, i.e., a microwave popcorn bag, the microwave interactive material 52 need not be patterned. However, it is contemplated that a patterned microwave interactive material 52 could be useful in other applications involving other types of food items 44 and other types of microwave food containers 10. Accordingly, both unpatterned and patterned microwave interactive material 52 may be utilized with the systems and methods described herein.

The microwave interactive material 52 functions to receive microwaves from a microwave source, e.g., a microwave oven, and to convert the microwave energy to heat. Accordingly, the microwave food container 10 can be placed in a microwave oven with the bottom portion 34 supported on a platform in the microwave oven and the popcorn kernels or other food item 44 and optional oil-producing substance 46 to be heated supported on and in contact with the bottom portion 34 above the microwave susceptor film 50 as described herein. When the microwave source is activated, the microwave interactive material 52 absorbs the microwave energy, converts it to heat, and applies the heat to the popcorn kernels or other food item 44 and to the optional oil-producing substance 46.

The microwave susceptor film 50 may also function to resist oils, grease, fats, juices, liquids, etc. from the popcorn or other food item 44 and the optional oil-producing substance 46 that are contained in the microwave food container 10, as well as various liquids, oils, juices, etc. that may be produced during the heating process, from penetrating into and through the fibrous material of the microwave food container 10 during transit, storage, and use of the microwave food container 10. Accordingly, as described further herein, the microwave susceptor film 50 may be positioned in the areas of the microwave food container 10 in which such oils, grease, etc. are likely to be in contact with the fibrous material and where the fibrous material is more susceptible to penetration and leakage, e.g., the bottom portion 34 and portions of the side portions 22 a, 22 b that are near or adjacent to the bottom portion 34.

As shown in FIGS. 5A-5C, 7A-7C, and 8A-8C the microwave susceptor film 50 may be comprised of a substantially rectangular shape with four peripheral edges. Thus, the microwave susceptor film 50 may comprise a first side 54, a second side 55, a top 56, and a bottom 57. The top 56 and bottom 57 are arranged opposite each other and the first and second sides 54, 55 are arranged opposite each other. The first side 54 may face towards the first end portion 12 and the second side 55 may face towards the second end portion 18 of the microwave food container 10.

The microwave interactive material 52 may be formed in a substantially square or slightly rectangular shape with opposed top and bottom edges and opposed first and second side edges. The top and bottom edges of the microwave interactive material 52 can be but are not necessarily substantially co-extensive with the corresponding top and bottom of the microwave susceptor film 50. The microwave interactive material 52 may extend laterally over only a portion of the surface area of the microwave susceptor film 50 such that the opposed first and second side edges of the microwave interactive material 52 are recessed inwardly from the corresponding first and second sides 54, 55 of the microwave susceptor film 50. In other words, the microwave susceptor film 50 may extend laterally beyond the opposite first and second side edges of the microwave interactive material 52 such that the portions of the surface area of the microwave susceptor film 50 that are at or near the opposite first and second edges of the microwave susceptor film 50 have no microwave interactive material 52. Similarly, in certain embodiments, the microwave susceptor film 50 may extend laterally beyond the opposite top and bottom edges of the microwave interactive material 52 such that the portions of the surface area of the microwave susceptor film 50 that are at or near the opposite top and bottom edges of the microwave susceptor film 50 have no microwave interactive material 52.

As best shown in FIGS. 6A-6C, the microwave susceptor film 50 may be laminated between the inner and outer layers 62, 64 of fibrous material at various locations within the microwave food container 10. By way of non-limiting example, the microwave susceptor film 50 may be positioned exclusively on the interior surface 40 of the bottom portion 34 of the microwave food container 10.

As shown in FIGS. 2A-2C and 4A-4C, the microwave susceptor film 50 may be oriented and arranged in the bottom portion 34 of the microwave food container 10 with the opposite first and second side edges of the microwave interactive material 52 substantially facing the opposite first and second side portions 22 a, 22 b of the microwave food container 10. In some embodiments, the microwave susceptor film 50 may extend laterally across the bottom portion 34 into one or both of the first and second side portions 22 a, 22 b, and upwardly along the first and second side portions 22 a, 22 b towards the top portion 28. More specifically the microwave susceptor film 50 may extend laterally across one or more fold lines 26 and into one or more fold areas 24 of the gussets 23 a, 23 b of the side portions 22 a, 22 b that are near or adjacent to the bottom portion 34. The microwave susceptor film 50 may act as a barrier to resist penetration of oil, grease, and/or other juices into and potentially through the fibrous material of the microwave food container 10 in those areas, which are particularly susceptible to such penetration.

The portion of the microwave susceptor film 50 that includes the microwave interactive material 52 may in some embodiments be contained completely in the bottom portion 34. In such embodiments, the microwave interactive material 52 does not cross any fold lines 26 and does not extend into the side portions 22 a, 22 b of the microwave food container 10. It is desirable to avoid the use of microwave interactive material 52 in areas having creases or folds, as the use of microwave susceptor film 50 in folded or creased areas on the microwave food container 10 could concentrate too much heat in those areas and potentially cause charring or burning of the microwave food container 10 and/or the food items 44 stored therein.

In some embodiments, the microwave susceptor film 50 may have a larger surface area than the microwave interactive material 52, with the microwave susceptor film 50 extending across folds, creases, and the like, but the microwave interactive material 52 remaining in the bottom portion 34. In some embodiments, both the microwave susceptor film 50 and the microwave interactive material 52 may be the same size, and both may be limited to the bottom portion 34. It may be desirable to limit the use of microwave susceptor film 50 to only the specific areas needed to most efficiently heat any food items 44, as the cost of microwave susceptor film 50 may increase overhead. However, as it still remains desirable to prevent leaks or liquid penetration in the fibrous material, oil-resistant areas 33 a, 33 b may instead be included so as to decrease overhead costs while continuing to protect various areas of the interior surface 40 of the microwave food container 10 from penetration by various liquids.

In some embodiments, it may be desirable to maximize the distance the microwave interactive material 52 extends laterally in the bottom portion 34 between the first and second side portions 22 a, 22 b without crossing the fold lines 26 between the bottom portion 34 and first and second side portions 22 a, 22 b. This may be accomplished by tapering, fading, or thinning the microwave interactive material 52 on the surface of the microwave susceptor film 50 at or near its opposite first and second side edges until no microwave interactive material remains near or at the fold lines 26. In other words, only the oil-resistant substance 32 or material, e.g., cellophane, of the microwave susceptor film 50 remains in those areas.

In some embodiments, the microwave susceptor film 50 may be limited to the bottom portion 34 of the microwave food container 10. In other embodiments, the microwave susceptor film 50 may extend at least partially into the first and second side portions 22 a, 22 b across the fold lines 26 and into the fold areas 24 of the gussets 23 a, 23 b that are near or adjacent to the bottom portion 34. In yet other embodiments, the microwave susceptor film 50 may extend into only one of the first and second side portions 22 a, 22 b. The microwave susceptor film 50 may extend a different distance into either or both of the side portions 22 a, 22 b across some or all of the fold areas 24 and fold lines 26 of the gussets 23 a, 23 b. In various embodiments, the microwave susceptor film 50 could extend into one or both of the side portions 22 a, 22 b and across more or fewer of the fold areas 24 and fold lines 26 of the gussets 23 a, 23 b of the side portions 22 a, 22 b than is shown in the exemplary embodiments illustrated in the figures, and accordingly all such variations regarding the location, positioning, and orientation of the microwave susceptor film 50 are considered to be within the scope of the disclosure.

In an exemplary embodiment, the microwave susceptor film 50 may extend only partially along the first and second side portions 22 a, 22 b between the first end portion 12 and the second end portion 18 of the microwave food container 10.

However, it is contemplated that in another example embodiment, the microwave susceptor film 50 may extend along the first and second side portions 22 a, 22 b substantially the entire distance between the first end portion 12 and the second end portion 18. It is contemplated and will be appreciated that in other embodiments, the microwave susceptor film 50 can extend along the first and/or second side portions 22 a, 22 b for any selected distance between the first and second end portions 12, 18.

As described herein, microwave food container 10 may be supported on a platform in a microwave oven prior to, during, and after heating. As the microwave interactive material 52 of the microwave susceptor film 50 receives microwaves and applies heat to the popcorn or other food item 44 and optionally to the oil-producing substance 46 in the microwave food container 10, the fold areas 24 of the gussets 23 a, 23 b in the opposed first and second side portions 22 a, 22 b of the microwave food container 10 will generally begin to unfold outward along the fold lines 26 as the microwave food container 10 expands.

As the fold areas 24 fold outwardly, the microwave susceptor film 50 may form an elongated substantially U-shaped tray structure within the microwave food container 10 in embodiments in which the microwave susceptor film 50 extends at least partially into the first and/or second side portions 22 a, 22 b. In other embodiments in which the microwave susceptor film 50 is exclusively positioned on the bottom portion 34, it may retain its flat configuration while the microwave food container 10 expands.

In embodiments in which the microwave susceptor film 50 forms an elongated U-shaped tray structure during expansion of the microwave food container 10, the bottom of the tray structure may extend both longitudinally and laterally along the bottom portion 34 between the opposed first and second side portions 22 a, 22 b. The bottom of the tray structure may comprise the portion of the surface of the microwave susceptor film 50 that includes the microwave interactive material 52. The opposing legs or sides of the tray may extend upwardly and longitudinally along the opposite first and second side portions 22 a, 22 b and more specifically across the fold lines 26 and the fold areas 24 that are near or adjacent to bottom portion 34.

The opposing legs or sides of the tray may not include any of the microwave interactive material 52 but may be comprised exclusively of oil-resistant material of the microwave susceptor film 50, e.g., cellophane. Liquefied oil from the oil-producing substance 46 if present as well as any other oils, liquids, or juices that may result from heating the popcorn or other food item 44 can drip or run into the tray structure and collect there without coming in contact with or penetrating through the outer layer 62 of fibrous material of the microwave food container 10. The microwave susceptor film 50 thus effectively resists penetration of the fibrous material of the microwave food container 10 by oil, grease, and/or other liquids or juices in the areas of the microwave food container 10 that are most susceptible to penetration.

It will be appreciated that although a particular example embodiment of the microwave susceptor film 50 is described, the microwave susceptor film 50 and its components may have different shapes and sizes than described, and can have different orientations and arrangements in the microwave food container 10 than described provided that they are consistent with performing the functions and achieving the objectives described herein. All such variations are thus intended to be encompassed within the scope of the present disclosure.

D. Blanks/Roll Stock

As described herein, some embodiments of the example microwave food container 10 may be constructed from a single piece of laminated fibrous material. FIGS. 5A-5C, 7A, and 8A illustrate blanks 11 from which the microwave food container 10 may be constructed, such as by folding along the fold lines 26 and adhering the various portions 22 a, 22 b, 28, 34 together (e.g., with glue or other adhesives). FIGS. 5A-5C, 7A, and 8A illustrate exemplary blanks 11 including all of the components for constructing a single microwave food container 10 may be contained. In some embodiments, individual blanks 11 may be produced and then manufactured into the microwave food container 10. In other embodiments, multiple blanks 11 may be produced together as part of a continuous roll stock 60 that is then cut to separate the blanks 11 prior to further manufacturing into the microwave food containers 10.

As shown in FIGS. 7B-7C and 8B-8C, the single piece of laminated material used to construct a single microwave food container 10 may in some embodiments be cut from a continuous roll stock 60 of the laminated material as part of the manufacturing process. Such a configuration may be desirable to increase the efficiency and speed of the manufacturing process, particularly where a large volume of microwave food container 10 are to be constructed in a short period of time. In some embodiments, the roll stock 60 may be manufactured at a first location and then sold to another party, or transported to other locations, prior to being cut into individual blanks 11.

FIGS. 7A-7C and 8A-8C illustrate blanks 11 that are repeated sequentially at spaced intervals in a continuous roll stock 60. For example, FIGS. 7A and 8A show the microwave susceptor film 50 with the interactive microwave material 52 laminated in the area of a single piece of the laminated material that corresponds to the bottom portion 34 of a single microwave food container 10 when constructed. FIGS. 7B-7C and 8B-8C illustrate these components repeated sequentially at spaced intervals in a continuous roll stock 60.

FIGS. 7A and 8A illustrate a blank 11 including adhesive areas 66 and locations for the fold areas 24 and fold lines 26 of the gussets 23 a, 23 b of the opposed first and second side portions 22 a, 22 b that will be used to construct a single microwave food container 10. FIGS. 7B-7C and 8B-8C illustrate each of these components repeated sequentially at spaced intervals on surface areas of a continuous roll stock 60 that correspond to the interior surfaces 40 of multiple microwave food containers 10. It should be readily apparent that the blank 11 shown in FIGS. 7A and 8A may be cut from the roll stock 60 of FIGS. 7B and 8B, respectively.

Cut lines 68 are illustrated at spaced intervals in the continuous roll stock 60 between sequential spaced areas that correspond to blanks 11 for single microwave food containers 10. The roll stock 60 may be unwound from a reel or roller or can be fed otherwise. The sequential spaced areas that correspond to blanks 11 for individual microwave food containers 10 may be cut from the continuous roll at the cut lines 68, and the resulting single pieces of laminated material corresponding to individual microwave food containers 10 can then be fed to an assembly line or to one or more individual work stations where the individual microwave food containers 10 can be constructed, such as by folding and use of adhesives.

As shown in FIGS. 7B-7C and 8B-8C, the entire continuous roll stock 60 may be comprised of the multi-layer laminated material from which individual microwave food containers 10 will be constructed. Thus, in the case of the present example embodiment the entire continuous roll stock 60 may be comprised of a multi-layer laminate with the outer layer 62 of fibrous material, the inner layer 64 of fibrous material, and the microwave susceptor film 50 adhered and laminated between the inner and outer layers 62, 64.

Once a piece of the multi-layer laminate material corresponding to a single microwave food container 10 (i.e., a blank 11) is cut from the continuous roll stock 60, it can be used to make a finished microwave food container 10. For example, in the embodiments shown in FIGS. 5A-5C, the blank 11 can be folded inwardly along the fold lines 26 in the areas corresponding to the opposing first and second side portions 22 a, 22 b to form the fold areas 24 of the gussets 23 a, 23 b of the first and second side portions 22 a, 22 b. The opposite side edges of the piece of material are then brought together with the surface of the material corresponding to the exterior surface 42 of the microwave food container 10 facing outwardly and the surface of the material corresponding to the interior surface 40 of the microwave food container 10 faces inwardly. The opposite side edges of the piece of material are overlapped to form an overlapping seam 30 and to create the top portion 28, bottom portion 34, and interior space 38 of the microwave food container 10. The overlapped edges are permanently adhered together at adhesive areas 66, 67 using a suitable non-toxic food grade adhesive. The opposite side adhesive 67 is on a side of the piece of material opposite of the side of the adhesive areas 66 where the adhesives areas 66, 67 are connected together to connect the overlapping seam 30.

Opposing surfaces of the top portion 28 and the bottom portion 34 at or near the second end portion 18 of the microwave food container 10 are brought together to form the second end portion seal 20 and are permanently adhered at adhesive areas 66 with a suitable non-toxic food grade permanent adhesive. The popcorn kernels or other food item 44 and optional oil producing substance 46 are introduced into the interior space 38 through the open first end portion 12 of the microwave food container 10 and are may be positioned on the interior surface 40 of the bottom portion 34 of the microwave food container 10 atop the microwave susceptor film 50.

The opposing surfaces of the top portion 28 and the bottom portion 34 at or near the first end portion 12 of the microwave food container 10 may then be brought together to form the first end portion seal 14 and potentially a first end opening 16 and may be temporarily adhered at adhesive areas 66 along all or a portion of the length of the seal 14 with an adhesive, such as a suitable non-toxic food grade temporary adhesive. With the first end portion 12 sealed, the microwave food container 10 is complete and the interior space 38 and the contents of the microwave food container 10 are isolated from the external environment. If desired, the first end portion 12 and the second end portion 18 of the completed microwave food container 10 may be folded inwardly over the top portion 28 or the bottom portion 34 in order to make the completed microwave food container 10 more compact for packaging, shipment, and storage.

E. Oil-Resistant Areas

Various types of food items 44 and/or oil-producing substances 46 may introduce various liquids, oils, juices, fats, and the like to the fibrous material of the microwave food container 10 when heated. While it is known to treat fibrous materials, such as the fibrous material from which the microwave food container 10 may be constructed, with various fluorocarbon-containing chemicals, such chemicals have become undesirable in many markets due to potential or perceived toxicity or carcinogenic properties. Examples of such chemicals include but are not limited to various fluorocarbons (sometimes referred to as perfluorocarbons or PFC's) and/or perfluoroalkyl or polyfluoroalkyl substances (sometimes referred to as PFA's).

However, given the high probability of contact between the fibrous material and such liquids, oils, juices, fats, and the like, it is desirable to seek other methods to provide resistance to oil and grease penetration that do not have the perception of being toxic or carcinogenic. Thus, it can be seen in the figures that the interior surface 40 of the microwave food container 10 may be treated with an oil-resistant substance 32 such as a sealant or the like that does not include any such potentially hazardous chemicals (e.g., PFC's or PFA's). Various types of non-toxic oil-resistant substances 32 may be utilized, such as but not limited to a sealant such as a wax or waxy substance which is applied to one or more oil-resistant areas 33 a, 33 b, 33 c, 33 d. Such oil-resistant substances 32 may be utilized in addition to the microwave susceptor film 50 to protect against liquid penetration (e.g., from oils or grease) in areas of the microwave food container 10 that would be particularly susceptible. The manner by which the oil-resistant substance 32 is applied to the fibrous material of the microwave food container 10 may vary in different embodiments. In some embodiments, the oil-resistant substance 32 may be applied as an additional layer to the interior surface 40 of the microwave food container 10. Such embodiments may utilize various types of waxes, films, or other layers of an oil-resistant substance 32 being applied to the interior surface 40 of the microwave food container 10. FIGS. 2A-2C and 4A-4C illustrate an embodiment in which the oil-resistant substance 32 forms a coating or layer of protection on the interior surface 40 of the microwave food container 10.

In other embodiments, the oil-resistant substance 32 may comprise a fluid such as an oil or other liquid-based treatment meant to penetrate the fibrous material of the interior surface 40 of the microwave food container 10. In such embodiments, the oil-resistant substance 32 may penetrate into the fibrous material and thus not form a discrete layer on top of the interior surface 40 of the microwave food container 10. FIGS. 6A-6C illustrate such an embodiment, in which it can be seen that the oil-resistant substance 32 has not formed a discrete layer, but has instead seeped or penetrated into the fibrous material itself to form a protective bond therewith.

By way of a non-limiting example, a coating of such an oil-resistant substance may be applied to the interior surface 40 of the inner layer 64 of fibrous material in one or more selected oil-resistant areas 33 a, 33 b, 33 c, 33 d. Oil-resistant areas 33 a, 33 b may correspond to the fold areas 24 and fold lines 26 in one or both side portions 22 a, 22 b, that may be more susceptible to oil and grease penetration than other areas.

While the microwave susceptor film 50 is known to provide protection against liquid penetration, the cost of covering the entire interior surface 40 of the microwave food container 10 with microwave susceptor film 50 may be prohibitive. It is thus desirable to only use the microwave susceptor film 50 in the areas of the microwave food container 10 which need to apply heat (e.g., the bottom portion 34 on which the food item 44 and oil-producing substance 46 is placed). Any remaining areas which are susceptible to liquid penetration during heating may then be treated with the oil-resistant substance 32, which in most cases is less costly than the microwave susceptor film 50.

The oil-resistant substance 32 may be utilized in portions or areas of the interior surface 40 of the microwave food container 10 where the microwave susceptor film 50 is not present. In this manner, the oil-resistant substance 32 may provide protection against penetration of the fibrous material in these areas in addition to the protection provided by the microwave susceptor film 50 as described herein.

In some embodiments, the entire interior surface 40 of the microwave food container 10 may be treated with the oil-resistant substance 32. In other embodiments, one or more oil-resistant areas 33 a, 33 b, 33 c, 33 d may be selected to be treated with the oil-resistant substance 32. In such embodiments, the use of the oil-resistant substance 32 may thus be limited to areas in which it is expected that liquid penetration may occur during heating, while leaving areas in which such penetration is not expected un-treated to save manufacturing costs.

Generally, one or more oil-resistant areas 33 a, 33 b, 33 c, 33 d may be formed by treating the fibrous material in those areas 33 a, 33 b, 33 c, 33 d with an oil-resistant substance 32. By applying an oil-resistant substance 32 to one or more areas 33 a, 33 b, 33 c, 33 d of the interior surface 40 of the microwave food container 10, portions of the microwave food container 10 which may be prone to penetration by undesirable fluids or the like may be protected without the requirement for microwave susceptor film 50.

In the exemplary embodiments shown in the figures, it can be seen that the microwave susceptor film 50 includes a first side 54, which may face towards the first side portion 22 a of the microwave food container 10, and a second side 55, which may face towards the second side portion 22 b of the microwave food container 10. One or more oil-resistant areas 33 a, 33 b may be positioned at or near one or both of the sides 54, 55 of the microwave susceptor film 50. Similarly, with reference to FIGS. 8A-8C, the microwave susceptor film 50 includes a top 56 that faces towards the first end portion 12 of the food container 10, and a bottom 57 that faces towards the second end portion 18 of the microwave food container 10. Additional oil-resistant areas, such as oil-resistant areas 33 c, 33 d may be positioned at or near one or both of the top 56 and bottom 57 of the microwave susceptor film 50. Oil-resistant areas may be placed at any other location with respect to the microwave susceptor film 50 without regard to the shape (e.g., rectangular, or non-rectangular) or the dimensions of the microwave susceptor film 50, e.g., the microwave susceptor film 50 itself does not place a limitation on the placement or pattern of the one or more oil-resistant areas.

FIGS. 1-4C illustrate exemplary, non-limiting embodiments of a microwave food container 10 which includes a plurality of oil-resistant areas 33 a, 33 b, each including an oil-resistant substance 32, at various positions along the interior surface 40 of the microwave food container 10. It should be appreciated that the embodiments shown in FIGS. 1-4C, and described herein, are merely for exemplary purposes and should not be construed as limiting with regard to the positioning and number of oil-resistant areas 33 a, 33 b, or their location in relation to the microwave susceptor film 50.

In the embodiment shown in FIGS. 2A, 4A, and 6A, it can be seen that a first oil-resistant area 33 a including an oil-resistant substance 32 is positioned adjacent to the first side 54 of the microwave susceptor film 50, between the microwave susceptor film 50 and the folding areas 24 and/or fold lines 26 of the first gusset 23 a of the first side portion 22 a. A second oil-resistant area 33 b including an oil-resistant substance 32 is positioned adjacent to the second side 55 of the microwave susceptor film 50, between the microwave susceptor film 50 and the folding areas and/or fold lines 26 of the second gusset 23 b of the second side portion 22 b.

Continuing to reference FIGS. 2A, 4A, and 6A, it can be seen that the first oil-resistant area 33 a is touching (i.e., in physical contact with) the first side 54 of the microwave susceptor film 50, and that the second oil-resistant area 33 b is touching (i.e., in physical contact with) the second side 55 of the microwave susceptor film 50. In such an embodiment, the first and second oil-resistant areas 33 a, 33 b each function as an extension of the microwave susceptor film 50 in opposite directions. As best illustrated in FIG. 2A, the first oil-resistant area 33 a extends to cover the bottom portion 34 and part of the first side portion 22 a of the microwave food container 10. The second oil-resistant area 33 b extends to cover the bottom portion 34 and part of the second side portion 22 b of the microwave food container 10. In such an embodiment, the first oil-resistant area 33 a provides protection for the fold line 26 defining the transition between the bottom portion 34 and the first side portion 22 a, and the second oil-resistant area 33 b provides protection for the fold line 26 defining the transition between the bottom portion 34 and the second side portion 22 b, both of which may be particularly susceptible to penetration by undesirable substances such as liquids or the like.

In the embodiment shown in FIGS. 2B, 4B, and 6B, it can be seen that a first oil-resistant area 33 a including an oil-resistant substance 32 is positioned adjacent to the first side 54 of the microwave susceptor film 50 and extends across the folding areas 24 and/or central fold line 26 of the first gusset 23 a of the first side portion 22 a, terminating prior to the fold line 26 defining the transition from the first side portion 22 a to the top portion 28. A second oil-resistant area 33 b including an oil-resistant substance 32 is positioned adjacent to the second side 55 of the microwave susceptor film 50 and extends across the folding areas 24 and/or central fold line 26 of the second gusset 23 b of the second side portion 22 b, terminating prior to the fold line 26 defining the transition from the second side portion 22 b to the top portion 28.

Continuing to reference FIGS. 2B, 4B, and 6B, it can be seen that the first oil-resistant area 33 a is touching (i.e., in physical contact with) the first side 54 of the microwave susceptor film 50, and that the second oil-resistant area 33 b is touching (i.e., in physical contact with) the second side 55 of the microwave susceptor film 50. In such an embodiment, the first and second oil-resistant areas 33 a, 33 b each function as an extension of the microwave susceptor film 50 in opposite directions as with the previously described embodiment, but for a further distance along the interior space 38 of the microwave food container 10.

As best illustrated in FIG. 2B, the first oil-resistant area 33 a extends to cover the bottom portion 34 and the majority of first side portion 22 a of the microwave food container 10. The second oil-resistant area 33 b extends to cover the bottom portion 34 and the majority of the second side portion 22 b of the microwave food container 10. In such an embodiment, the first oil-resistant area 33 a provides protection for the fold line 26 defining the transition between the bottom portion 34 and the first side portion 22 a, and the second oil-resistant area 33 b provides protection for the fold line 26 defining the transition between the bottom portion 34 and the second side portion 22 b, both of which may be particularly susceptible to penetration by undesirable substances such as liquids or the like.

The first oil-resistant area 33 a extends across the first gusset 23 a and its fold areas 24 and fold line 26, while the second oil-resistant area 33 b also extends across the second gusset 23 b and its fold areas 24 and fold line 26. In this manner, substantially all of the first and second side portions 22 a, 22 b may be protected. Although not shown, in some embodiments, the first and second oil-resistant areas 33 a, 33 b may further extend across part of or the entire top portion 28.

In the embodiment shown in FIGS. 2C, 4C, and 6C, it can be seen that the microwave susceptor film 50 itself is elongated so as to cover the fold lines 26 between the respective side portions 22 a, 22 b and the bottom portion 34. An area central to the microwave susceptor film 50 includes a microwave interactive material 52, with the microwave susceptor film 50 extending outwardly in two directions from the central microwave interactive material 52. It should be appreciated that the ratio between the sizes of the microwave susceptor film 50 and the microwave interactive material 52 may vary in different embodiments. In some embodiments, the microwave interactive material 52 may similarly extend across the fold lines 26.

Continuing to reference FIGS. 2C, 4C, and 6C, it can be seen that a first oil-resistant area 33 a treated with an oil-resistant substance 32 is positioned near, but not physically touching, the first side 54 of the microwave susceptor film 50. Similarly, a second oil-resistant area 33 b treated with an oil-resistant substance 32 is positioned near, but not physically touching, the second side 55 of the microwave susceptor film 50.

Thus, the first oil-resistant area 33 a is distally spaced with respect to the first side 54 of the microwave susceptor film 50 and the second oil-resistant area 33 b is distally spaced with respect to the second side 55 of the microwave susceptor film 50. The distance or gap between the respective sides 54, 55 of the microwave susceptor film 50 and the respective first and second oil-resistant areas 33 a, 33 b may vary in different embodiments and should not be construed as limited by the exemplary figures.

With reference to FIGS. 2C, 4C, and 6C, it can be seen that such an exemplary embodiment utilizes first and second oil-resistant areas 33 a, 33 b which extend across the entire upper half of the respective first and second side portions 22 a, 22 b. The first and second oil-resistant areas 33 a, 33 b thus extends across the fold areas 24 and fold lines 26 of the respective gussets 23 a, 23 b and across the fold lines 26 defining the transition between the respective side portions 22 a, 22 b and the top portion 28 of the microwave food container 10. In such an embodiment, it can be seen that each fold line 26 of the microwave food container 10 is protected by either microwave susceptor film 50 or an oil-resistant area 32 a, 32 b.

FIGS. 8A-8C illustrate exemplary, non-limiting embodiments of a microwave food container 10 which the oil-resistant areas 33 a, 33 b, as well as oil-resistant areas 33 c, 33 d, each including an oil-resistant substance 32, at various positions along the interior surface 40 of the microwave food container 10. The illustrated embodiments are merely for exemplary purposes and should not be construed as limiting with regard to the positioning and number of oil-resistant areas 33 a, 33 b, 33 c, 33 d, or their location in relation to the microwave susceptor film 50.

In the embodiments shown in FIGS. 8A-8C, the first and second oil-resistant areas 33 a, 33 b, are positioned relative to the microwave susceptor film 50 and the microwave food container 10 as described elsewhere herein. The third oil-resistant area 33 c including an oil-resistant substance 32 is positioned adjacent to the top 56 of the microwave susceptor film 50, between the microwave susceptor film 50 and the first end portion 12 of the microwave food container 10. The fourth oil-resistant area 34 d including an oil resistant substance 32 is positioned adjacent to the bottom 57 of the microwave susceptor film 50, between the microwave susceptor film 50 and the second end portion 18 of the microwave food container 10.

Continuing with FIGS. 8A-8C, it can be seen that the third oil-resistant area 33 c is touching (i.e., in physical contact with) the top 56 of the microwave susceptor film 50, and that the fourth oil-resistant area is touching (i.e., in physical contact with) the bottom 57 of the microwave susceptor film 50. In such an embodiment, the third and fourth oil-resistant areas 33 c, 33 d each function as an extension of the microwave susceptor film 50 in opposite directions. In the illustrated embodiments, each of the third and fourth oil-resistant areas 33 c, 33 d is also in contact with each of oil-resistant areas 33 a, 33 b providing a continuous oil-resistant perimeter about the microwave susceptor film 50. In certain embodiments, the oil-resistant areas 33 a, 33 b, 33 c, 33 d, may have a consistent length and width while in other embodiments one or more of the oil-resistant areas 33 a, 33 b, 33 c, 33 d may have a different length and/or width from the other of the oil-resistant areas 33 a, 33 b, 33 c, 33 d. In certain embodiments, the third and fourth oil-resistant areas 33 c, 33 d, are not in contact with the first and second oil-resistant areas 33 a, 33 b. In certain embodiments, the third and fourth oil-resistant areas 33 c, 33 d are near but not in direct physical contact the microwave susceptor film 50.

It can be seen in FIGS. 8A-8C that the third oil-resistant area 33 c covers the bottom portion 34 of the microwave food container 10 in the location between the top 56 of the microwave susceptor film 50 and the first end portion 12 of the microwave food container 10. The fourth oil-resistant area 33 d covers the bottom portion 34 of the microwave food container 10 in the location between the bottom 57 of the microwave susceptor film 50 and the second end portion 18 of the microwave food container 10. In certain embodiments, one or both of the third and fourth oil-resistant areas 33 c, 33 d extends to the edge of the respective first and second end portions 12, 18 of the microwave food container 10. In certain embodiments, one or both of the third and fourth oil-resistant areas 33 c, 33 d extend only part-way to the edge of the respective first and second end portions 12, 18 of the microwave food container 10.

The preceding description and accompanying figures are merely non-limiting examples of the positioning, location, size, and orientation of the oil-resistant areas 33 a, 33 b, 33 c, 33 d that may be utilized to protect the interior surface 40 of a microwave food container 10 from penetration by liquids such as fats, oils, grease, juices, and the like. It should be appreciated that various other arrangements may be utilized, and thus the figures and accompanying description should not be construed as limiting with regard to the positioning, location, size, and orientation of the oil-resistant areas 33 a, 33 b, 33 c, 33 d. In some embodiments, the oil-resistant areas 33 a, 33 b, 33 c, 33 d may in some locations overlap with the microwave susceptor film 50. In further embodiments, the oil-resistant areas 33 a, 33 b, 33 c, 33 d may extend to cover the entirety, or substantially the entirety, of the interior surface 40 of the microwave food container 10.

F. Operation of Preferred Embodiment

While the following description relates to a microwave food container 10 comprised of a microwave popcorn bag, it should be appreciated that the same concepts may be applied to microwave food containers 10 designed for other types of food items 44. It should also be appreciated that, while the following description relates to a microwave food container 10 comprising an inflatable bag design made of a fibrous material, various other microwave food containers 10 may benefit from the systems and methods described in, such as but not limited to a rigid microwave food container 10 having a porous or other penetration-prone surface that would benefit from protection of an oil-resistant substance 32 in one or more oil-resistant areas 33 a, 33 b, 33 c, 33 d.

With regards to manufacturing, blanks 11 may be formed by flat sheets which include fold lines 26, microwave susceptor film 50 including or not including microwave interactive material 52, and/or one or more oil-resistant areas 33 a, 33 b, 33 c, 33 d including an oil-resistant substance 32. The manner of manufacturing may vary in different embodiments. In some embodiments, individual blanks 11 may be produced. In other embodiments, a continuous roll stock 60 comprising multiple blanks 11 interconnected by cut lines 68 may be produced. In such embodiments, the blanks 11 may be cut from the continuous roll stock 60 at the cut lines 68 either at the manufacturer or by a purchaser.

Generally, the microwave food container 10 will be formed by folding the blanks 11 into substantially the form shown in FIG. 1 . Any food items 44 and/or oil-producing substances 46 may be placed onto the blank 11 prior to folding into a microwave food container 10, or may be placed into the microwave food container 10 during or after folding. The microwave food container 10 may be folded into a more compact form for sale, and covered or wrapped in a plastic sheet or other outer covering meant to maintain freshness and prevent the food items 44 from going stale.

The end user will generally receive the microwave food container 10 in a folded state. The end user will thus first unfold the microwave food container 10 into substantially the flat, compact form shown in FIG. 1 . The microwave food container 10 may then be placed in a suitable microwave oven, with the bottom portion 34 generally being positioned on and supported by a platform within the microwave oven. The microwave oven may then be activated so as to apply microwave energy to the microwave food container 10.

While the microwave oven is activated, the microwave interactive material 52 of the microwave susceptor film 50 receives microwave energy, converts the microwave energy to heat, and applies the heat to the food items 44 and oil-producing substance 46 in the interior space 38 of the microwave food container 10. In an embodiment in which the food items 44 are comprised of popcorn kernels, as the popcorn kernels and oil-producing substance 46 heat up, the kernels begin to pop, producing gases in the interior space 38 of the microwave food container 10 and filling the interior space 38. The gases are allowed to vent at least partially through the first end portion opening 16 in the first end portion seal 14 and the outward forces produced in the interior space 38 cause the folding areas 24 of the gussets 23 a, 23 b of the first and second side portions 22 a, 22 b to unfold outwardly and the microwave food container 10 to expand as described herein and as shown in FIGS. 3-4C.

As the food item 44 and oil-producing substance 46 are heated, various liquids in the form of oils and melted butter will generally be produced. Such liquids would normally penetrate the fibrous material forming the microwave food container 10 without protection. In the embodiments shown and described herein, a combination of the microwave susceptor film 50 and the oil-resistant areas 33 a, 33 b, 33 c, 33 d will protect the portions of the microwave food container 10 that would be most susceptible to such penetration. The microwave susceptor film 50 and/or oil-resistant areas 33 a, 33 b may separately or together form a substantially U-shaped tray on the bottom portion 34 and along part of or all of the first and second side portions 22 a, 22 b. Such a tray collects oil, grease, and other juices that might be produced during the heating process and resists them coming into contact with and penetrating through the fibrous material of the microwave food container 10.

The microwave oven can remain activated for a period of time suitable to cause substantially all of the popcorn kernels to pop. Upon completion of the heating process, the first end portion opening 16 can be expanded and the popcorn or other food items 44 may be accessed and removed from the interior space 38 if desired for consumption.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice or testing of the various embodiments of the present disclosure, suitable methods and materials are described above. All patent applications, patents, and printed publications cited herein are incorporated herein by reference in their entireties, except for any definitions, subject matter disclaimers or disavowals, and except to the extent that the incorporated material is inconsistent with the express disclosure herein, in which case the language in this disclosure controls. The various embodiments of the present disclosure may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the various embodiments in the present disclosure be considered in all respects as illustrative and not restrictive. Any headings utilized within the description are for convenience only and have no legal or limiting effect. 

What is claimed is:
 1. A microwave popcorn bag, comprising: a bottom portion including an interior surface adapted to support a plurality of popcorn kernels; a top portion adapted to contain the plurality of popcorn kernels; a first side portion connected between the bottom portion and the top portion; a second side portion connected between the bottom portion and the top portion; an interior space defined between the bottom portion, the top portion, the first side portion, and the second side portion; a microwave susceptor film on the interior surface of the bottom portion, wherein the microwave susceptor film is adapted to receive microwaves and apply heat to the plurality of popcorn kernels; a first oil-resistant area on a first side of the microwave susceptor film, wherein the first oil-resistant area comprises an oil-resistant substance; and a second oil-resistant area on a second side of the microwave susceptor film, wherein the second oil-resistant area comprises the oil-resistant substance.
 2. The microwave popcorn bag of claim 1, wherein the first oil-resistant area and the second oil-resistant area are each on the bottom portion.
 3. The microwave popcorn bag of claim 1, wherein the first oil-resistant area is adjacent to the first side of the microwave susceptor film.
 4. The microwave popcorn bag of claim 3, wherein the second oil-resistant area is adjacent to the second side of the microwave susceptor film.
 5. The microwave popcorn bag of claim 1, wherein the first oil-resistant area is distally spaced with respect to the first side of the microwave susceptor film.
 6. The microwave popcorn bag of claim 5, wherein the second oil-resistant area is distally spaced with respect to the second side of the microwave susceptor film.
 7. The microwave popcorn bag of claim 1, wherein the first oil-resistant area extends from the bottom portion to the first side portion, and wherein the second oil-resistant area extends from the bottom portion to the second side portion.
 8. The microwave popcorn bag of claim 1, wherein the first side portion comprises a first gusset with a first fold, and wherein the first oil-resistant area extends across the first fold.
 9. The microwave popcorn bag of claim 8, wherein the second side portion comprises a second gusset with a second fold, and wherein the second oil-resistant area extends across the second fold.
 10. The microwave popcorn bag of claim 1, wherein the oil-resistant substance does not include perfluoroalkyl or polyfluoroalkyl substances.
 11. The microwave popcorn bag of claim 1, wherein the first oil-resistant area extends into the first side portion an entire distance between the bottom portion and the top portion, and wherein the second oil-resistant area extends into the second side portion the entire distance between the bottom portion and the top portion.
 12. The microwave popcorn bag of claim 1, wherein the first oil-resistant area, the second oil-resistant area, and the microwave susceptor film are each the same size.
 13. The microwave popcorn bag of claim 1, wherein the microwave susceptor film includes a microwave interactive material.
 14. The microwave popcorn bag of claim 1, wherein the bottom portion, the top portion, the first side portion, and the second side portion are each comprised of a fibrous material.
 15. The microwave popcorn bag of claim 1, further comprising a third oil-resistant area near a top of the microwave susceptor film, wherein the third oil-resistant area comprises an oil-resistant substance.
 16. The microwave popcorn bag of claim 15, further comprising a fourth oil-resistant area near a bottom of the microwave susceptor film, wherein the fourth oil-resistant area comprises the oil-resistant substance.
 17. A microwave popcorn bag, comprising: a bottom portion including an interior surface adapted to support a plurality of popcorn kernels; a top portion adapted to contain the plurality of popcorn kernels; a first side portion connected between the bottom portion and the top portion, wherein the first side portion includes a first gusset and a first fold; a second side portion connected between the bottom portion and the top portion, wherein the second side portion includes a second gusset and a second fold; an interior space defined between the bottom portion, the top portion, the first side portion, and the second side portion; a microwave susceptor film on the interior surface of the bottom portion, wherein the microwave susceptor film is adapted to receive microwaves and apply heat to the plurality of popcorn kernels; a first oil-resistant area including an oil-resistant substance extending between the bottom portion and the first side portion; and a second oil-resistant area including the oil-resistant substance extending between the bottom portion and the second side portion.
 18. The microwave popcorn bag of claim 17, wherein the first oil-resistant area extends across the first fold, and wherein the second oil-resistant area extends across the second fold.
 19. The microwave popcorn bag of claim 17, wherein the first oil-resistant area is adjacent to a first side of the microwave susceptor film, and wherein the second oil-resistant area is adjacent to a second side of the microwave susceptor film.
 20. The microwave popcorn bag of claim 17, wherein the first oil-resistant area is distally spaced with respect to a first side of the microwave susceptor film, and wherein the second oil-resistant area is distally spaced with respect to a second side of the microwave susceptor film.
 21. The microwave popcorn bag of claim 17, wherein the first oil-resistant area extends from the first side portion to the top portion, and wherein the second oil-resistant area extends from the second side portion to the top portion.
 22. The microwave popcorn bag of claim 17, wherein the oil-resistant substance does not include perfluoroalkyl or polyfluoroalkyl substances.
 23. The microwave popcorn bag of claim 17, further comprising a third oil-resistant area including the oil-resistant substance positioned intermediate the microwave susceptor film and a first end portion of the microwave popcorn bag.
 24. The microwave popcorn bag of claim 23, further comprising a fourth oil-resistant area including the oil-resistant substance positioned intermediate the microwave susceptor film and a second end portion of the microwave popcorn bag. 